Why:
- Life Regen just got a huge buff. (Details below)
- Vortex initial hit AND DOT benefits from spell damage, (which we will scale with strength)
- Righteous Fire damage scales with Life, (which we will scale with strength)
- Life is the opposite of death

Cons:
- Relatively small AOE. Does not blow up screen.
- Needs to be in relatively close range to attack.

How we scale Vortex damage:

Spoiler

We cale Vortex damage primarily using Strength and Righteous Fire.

Strength can benefit spell damage via:
http://pathofexile.gamepedia.com/Iron_Will_Support This support gem will give 58% increased spell damage, more importantly Strength's damage bonus applies to Spell damage. Since we will get a total of about 1000 strength this will give us just short of 250% spell damage.

But wait, it gets better:
http://pathofexile.gamepedia.com/Doon_Cuebiyari This badboy gives us another 125% damage on top of the 250% spell damage. Also it gives some strength and quality of life cast speed.

We will socket Vortex together with Elemental Focus and Increased area of effect for a 49% MORE Area Damage modifier and qality of life.

Note that all this damage scaling applies to both the initial hit as well as the degen portion of the damage.

How we scale Righteous Fire damage:

Spoiler

We are not actually scaling the RF damage as much as a 'Pure RF build' would. The reason is that RF does not scale with spell damage. We do however get:
- 10k life
- 125% Incresed Damage from Doon Quebayari
- 49% More Elemental Damage from Elemental Focus
- 69# Increased burning damage from Increased Burning Damage Support gem

How we stay alive;

Spoiler

First off we get a really big life pool. Secondly we get a metric shit ton of regen.

In order to combat the degen from Righteous fire you need about 12% regen, 1% maxres to fire on the tree, and a lvl 17+ Purity of fire. We get all that and then some.

Spoiler

Ascendancy:
From the ascendancy tree alone we get 1.5% life regen + 0.5% life regen per endurance charges. We will get nine endurance charges totaling 6% from ascendancy alone.

Passive Tree:
From the passive tree we get 13.2% life regen + 0.2% per endurance charge for a total of 15%

Kaom's Way:
The fated version of Kaoms sign gives us 0.4% per endurance charge per ring for a whopping total of 7.2% life regen.

In total, we get about 10K life and a little over 28% life regen!

How we have fun while leveling

Spoiler

Here is a super big plus for this build. It is fun to level.

This time, instead of leveling your melee build as a caster you will level your caster as a melee character.

The key to happy leveling for us is the Pillars of the Caged God unique staff. This badboy scales damage with strength which lets you fill out your tree without any detours AND it will do really good damage meanwhile. What that means is you will be tanky and have good clearspeed.

So, here are the steps for leveling.
1. Start as a marauder
2. Get yourself to lvl 13 any way you can
3. Buy yourself a Pillar of the Caged God, a Meginords Girdle and some phys damage jewelery
4. Get Resolute Technique. Your tree should look something like: http://poeurl.com/Glv
5. Play around with skills you like. I prefer Sunder. Earthquake and Ground Slam are good too
Link with things that scale with phys damage, i.e. Melee Physical Attack Damage, Added Fire, WED..
Run with Herald of Ash
Run Clarity and get yourself a Survival Secrets to sustain mana costs
Aim for a passive tree that looks something like this: http://poeurl.com/Glz
If you want you can get less regen and more life, but make sure you have enough regen to sustain RF
6. Bash monsters heads in, blow stuff up. Cause general mayhem while leveling yourself and your gems
7. Become lvl 65. Buy yourself a Rise of the Phoenix.
8. Buy yourself an Essence Worm amulet and socket your Purity of Fire.
9. PROFIT

As a general rule you want to avoid Energy shield on your gear as it increases your life degeneration. It does also boost your RF damage however and can be easier to colour, so you need to make a judgement call.

Head:

Body:
Kaoms Heart is best in slot.
Belly of the beast is cheaper and very good.
If you can 6-link Belly of the Beast and off colour it you can socket your vortex here, but it will be expensive.

Although a six linked Belly of the Beast or a Kaoms heart help the build out you don't need to spend a lot to make this build work. It should not require more than what you can save up during leveling.

Cool build idea, I'm actually making a build similar now. Just one thing, Essence Worm is a ring not an amulet, so you can only have 1 Kaom's Way, or run without PoF. Both are probably viable with this level of regen. I'm leaning towards the Essence Worm, just to make it easier on regen needs at the start, possibly swapping to Kaom's later on. With just the 1 Kaom's, you still have 8 Endurance charges, for a massive 8.8% life regen from those alone.

With enough regen, you can also swap to Saffel's Frame instead of Phoenix (or just have it in a weapon swap for painful caster situations!), or a rare shield with Leo mod -% damage over time taken, which is nice for a lategame option!

You can grab some lightning damage to attacks somewhere (gloves/amulet), and run a leap slam to apply EE to both fire and cold resistance for even more degen damage, if damage is ever a problem.

i followed most of this build and it seems that the clear speed is great with good health pool (lvl.75-5.3k).

but the changes i made is i didnt run BM i run elemental weakness with as reserved mana + purity of fire. In addition, i used pyre ring ( to scale vortex DPS) + kaom way ring. However so proc EE i use blade vortex linked with inc aoe + inc duration + added lightning damage where the reason behind that is not to Proc EE on fire (vortex) or cold (vortex DoT).

second thing modified is Ele.Overloard which is great for DPS boost.

you can check out my character by clicking on my account(Char name: KUROCODAIN ) for tree + gear.